Fabrication And Properties Of Garnet-based Long Afterglow Luminescent Transparent Ceramics

Yttrium aluminum gallium garnet Y₃Al_5-xGa_xO₁₂（x=0,1,2,3,4）ceramics is currently one of the materials with the long afterglow luminescence potential.Among them,Y₃Al₂Ga₃O₁₂:Ce,Cr can reach thousands of mcd/m~2output of Luminance and maintains more than 800 minutes afterglow duration,which is far better than traditional long afterglow powder and other materials.Because of its high hardness,wear resistance and excellent waterproof performance,long afterglow ceramics can be used in more harsh environments.It is worth exploring to improve the maximum luminance and afterglow duration while maintaining the advantages of yttrium aluminum gallium garnet in long afterglow applications.To improve the long afterglow performance of ceramics,the densification process of the ceramics,the ratio of impurity ions,sintering system and various post-treatments such as HIP,annealing,etc.should be explored.In this thesis,different amounts of sintering aid Y₃Al₂Ga₃O₁₂:0.5%Ce,0.05%Cr long afterglow luminescent ceramics are prepared by solid-phase reaction combined with air pre-sintering,auxiliary component 1（0.8wt%TEOS,0.08wt%Mg O）and auxiliary component 2（0.5wt%TEOS,0.1wt%Mg O）;different Ce content(Y_1-xCe_x)₃(Al_0.9995Cr_0.0005)₂Ga₃O₁₂（X=0.001,0.002,0.003,0.005）long afterglow luminescent ceramics are prepared by solid-phase reaction combined with air pre-sintering;different Ce and Cr content(Y_1-xCe_x)₃(Al_1-YCr _Y)₂Ga₃O₁₂（X=0.0005,0.001,0.002,0.003,Y=0.00025,0.0005,0.001,0.002）long afterglow luminescent ceramics are prepared by solid-phase reaction combined with air pre-sintering.The addition of sintering aids,the content of Ce and Cr ions,sintering temperature,HIP post-treatment and annealing in different atmospheres affect the densification process,optical properties,afterglow properties of ceramics were explored.The main conclusions are as follows:（1）Y₃Al₂Ga₃O₁₂:0.5%Ce,0.05%Cr with 0.8wt%TEOS,0.08wt%Mg O sintering aid ceramics can achieve high density after pre-sintering at 1625℃×20h and1650℃×20h,The linear transmittance of the ceramic sample of 1625℃×20h+HIP is52.7%@1200nm（2.1mm）,the linear transmittance of the ceramic sample of1650℃×20h+HIP,is 47.0%@1200nm（2.1mm）.It is excited by ultraviolet light.After stopping the excitation,the transparent ceramics have a higher afterglow duration than the pre-sintering ceramics with the same pre-sintering temperature.（2）Different Ce content(Y_1-xCe_x)₃(Al_0.9995Cr_0.0005)₂Ga₃O₁₂（X=0.001,0.002,0.003,0.005）is prepared by solid-phase reaction combined with air pre-sintering method and annealing in different atmospheres.After HIP,The linear transmittance of the ceramic sample of YGAG（X=0.005）ceramic samples reaching 34.22%at 1200nm（sample thickness 2.1 mm）;the highest transmittance after argon hydrogen annealing is YGAG（X=0.005）ceramic samples reaching 36.40%at 1200 nm（The sample thickness is 2.1 mm）;the highest transmittance after air annealing is YGAG（X=0.003）,the ceramic sample reaches 37.34%at 1200 nm（the sample thickness is2.1 mm）.After pre-sintering,YGAG（X=0.001）ceramic has the luminance after excitation up to 5165.0 mcd/m~2,the afterglow duration of YGAG（X=0.001）is 745mins;after HIP,YGAG（X=0.002）ceramic has the luminance after excitation is3614.0 mcd/m~2,And the afterglow duration of YGAG（X=0.001）is 865 mins;after argon hydrogen annealing,YGAG（X=0.003）ceramic has the luminance after excitation is 1956.0 mcd/m2,the afterglow duration of YGAG（X=0.002）is 380 mins;after air annealing,YGAG（X=0.002）ceramic has the luminance after excitation is4424.0 mcd/m2,while the afterglow duration of YGAG（X=0.001）is 1390 mins.（3）Prepare(Y_1-xCe_x)₃(Al_1-YCr _Y)₂Ga₃O₁₂（X=0.0005,0.001,0.002,0.003,Y=0.00025,0.0005,0.001,0.002）ceramics by solid-phase reaction combined with air pre-sintering method.After HIP,the highest transmittance is YGAG（X=0.002,Y=0.002）ceramic samples,and the transmittance reaches 30.17%at 1200 nm（sample thickness 2.1 mm）.After pre-sintering,YGAG（X=0.001,Y=0.0005）ceramic has the luminance after excitation up to 5352.0 mcd/m~2,the afterglow duration of YGAG（X=0.0005,Y=0.0005）is 815 mins;after HIP,YGAG（X=0.003,Y=0.00025）ceramic has the luminance 5084.0 mcd/m~2,and the afterglow duration of YGAG（X=0.0005,Y=0.00025）is 1425 mins;after air annealing,YGAG（X=0.003,Y=0.00025）ceramic has the luminance after excitation is 6055.0 mcd/m~2,while the afterglow duration of YGAG（X=0.0005,Y=0.001）is 1440 mins.